right, this is difficult if you dont know the song however this is how i got the achievement and it works quite well,
Deck used> Euphoria Deck
Optional Deck>Multiplyer (not recommended)
you need to be able to do the whole intro part without missing a note...this is the bit where it goes >> GGGGGGGGGGGGGGG *crossfades with red* to the part when it goes pretty much impossible to hit with the wierd GRBGRBGRB combo....however when doing the beginning you need to keep turning the Multiplyer dial thingy to get tha x8 this honestly gets you near 1 star or over 1 star quite quickly.....then you obvs need to hit as many notes possible....untill you get to the Crossfade section in the middle....(before hitting this i recommend getting atleast 1 of the 2 perfect regions) with this Crossfade section it comes down 3 times.....the first time its easish with just the crossfading (DONT USE EUPHORIA HERE!) when the second one starts soon as you press the 1st Red button activate euphoria....the euphoria will now crossfade the last 2 sections for you racking up an easy x8 bonus concentrate on hitting the red mainly...Also to this if you manage to have a rewind use it at the end of the 3rd crossfade section this will help rake in even more points(when theres ANY red button freestyle...spam the red button as much as possible...more hits the more points and it would help witha x8 multiplyer or x4) from here you should be around 4stars or just above it...now this is the hardish bit....you honestly just need to practice the combo of crossfading and the double buttons till the end...hopefully follow this and you will get 5 Stars...soon as you do hit the 5 stars....you can literally relax for the rest of the song....when you finish the achievement will pop up giving you 18G :O !!!!!!!!!!!!!! Sorry i have no video however i will be recording this to explain easier if anyone needs help .... message my GT and i will gladly show you how...in a Multiplayer match ...
TIP ** use rewinds as frequent as possible to gain any extra points as possible however keep atleast one for the 3rd crossfade section to basically gain more points**